Problem: Khan.scratchpad.disable(); For every level Kevin completes in his favorite game, he earns $800$ points. Kevin already has $450$ points in the game and wants to end up with at least $3390$ points before he goes to bed. What is the minimum number of complete levels that Kevin needs to complete to reach his goal?
Answer: To solve this, let's set up an expression to show how many points Kevin will have after each level. Number of points $=$ $ $ Levels completed $\times$ Points per level $+$ Starting points Since Kevin wants to have at least $3390$ points before going to bed, we can set up an inequality. Number of points $\geq 3390$ Levels completed $\times$ Points per level $+$ Starting points $\geq 3390$ We are solving for the number of levels to be completed, so let the number of levels be represented by the variable $x$ We can now plug in: $x \cdot 800 + 450 \geq 3390$ $ x \cdot 800 \geq 3390 - 450 $ $ x \cdot 800 \geq 2940 $ $x \geq \dfrac{2940}{800} \approx 3.67$ Since Kevin won't get points unless he completes the entire level, we round $3.67$ up to $4$ Kevin must complete at least 4 levels.